The name of a package
Keep package names short and meaningful.
Don't use underscores, they make package names long.
io/ioutil not io/util
suffixarray not suffix_array
Don't overgeneralize. A util package could be anything.
The name of a package is part of its type and function names.
On its own, type Buffer is ambiguous. But users see:
buf := new(bytes.Buffer)
Choose package names carefully.
Choose good names for users.